I myself have been on the look out for a JJ for sometime. These two are current or recent. I have concerns for different reasons per item but will refrain from further comment until Ballroom adds his invaluable take.
Separately, given that they all passed at 27, in terms of availability of genuine signed items, I would say
1-Jimi Hendrix
2-Janis Joplin
3-Jim Morrison
One being most available and three being least. I would be interested to hear from others.
i do believe that genuine Janis signatures have been undervalued for a while although that trend has been changing somewhat of late, if recent auction results are anything to go by.
Thanks